Chemodynamical evoluation of dwarf spheroidal galaxies

This project is aimed at studying the physical mechanisms that lead to the formation of gas-poor dwarf spheroidal galaxies with abnormally low abundance ratios and very metal-poor stars. For these purposes, we will employ numerical hydrodynamics simulations using an upgraded version of the applicant's code, which will include live gas, stellar and dark matter components, non-equilibrium chemical reaction network, and ionizing radiation transfer. We will investigate the dynamical, chemical, and photometric evolution of dwarf galaxies with various initial conditions and gas (metal) removal mechanisms. In particular, dwarf galaxies with different masses, rotation rates, star formation histories, and configurations of the dark matter halo will be considered. We will perform a comparative study of the efficiency of gas and metal removal by supernova explosions, ram pressure stripping, and tidal interactions. We will construct evolutionary tracks of our model galaxies in the color-magnitude diagram and compare them with the known photometric properties of the nearby dwarf spheroidal and dwarf irregular galaxies. Several possible reasons for abnormally low abundance ratios in dwarf spheroidal galaxies (as compared to those of the Milky Way), such as differential ejection of metals by supernova explosions, peculiar initial mass functions and metal-poor gas infall, will be numerically investigated. Finally, we will study the formation efficiency of very metal-poor stars in dwarf protogalaxies via cooling (due to gas molecularization) and fragmentation of a shell created by the explosion of the first stars.